Estimating the Ionization Rate of the Upper Atmosphere During X‐Class Solar Flares

This article examines the impact of solar flare electromagnetic radiation on the state and dynamics of the Earth's upper atmosphere and the applicability of experimental and theoretical methods for assessing changes in the upper ionosphere. One of the most important parameters of ionospheric disturbances is the ionization rate. The article presents data from calculating vertical profiles of the electron production rate for altitudes from 60 to 600 km for two X‐class solar flares that occurred on 6 September 2017, using the FISM2 Flare solar irradiance model and the NRLMSISE‐00 neutral atmosphere model. The results are verified using experimental measurements of variations in the ionospheric total electron content using a GNSS receiver located at the Mikhnevo mid‐latitude geophysical observatory. Two types of estimates of the ionization rate were obtained: without and with the recombination process taken into account. It was demonstrated that the combination of the FISM2 Flare and the NRLMSISE‐00 models qualitatively correctly predicts the temporal dynamics of the ionization rate. In general, the results obtained demonstrate the validity of the proposed approaches and open the possibility of further research in this area.